Sue Says
Check your rhubarb isnt too shaded from the sun as this may be causing the spindly growth; rhubarb flourishes in full sun and will grow poorly in the shade. Rhubarb also requires very high nitrogen levels in the soil so its advisable to apply a heavy dressing of manure or compost every autumn or spring. In addition give your rhubarb a feed in spring with a fertiliser high in nitrogen http://www.thompson-morgan.com/sundries1/product/kww2550/1.html . Its also worth mentioning that rhubarb likes a free draining soil – waterlogged soil can encourage the crown to rot, so improve drainage if necessary.